1、Designation: F 495 99a (Reapproved 2004)Standard Test Method forWeight Loss of Gasket Materials Upon Exposure to ElevatedTemperatures1This standard is issued under the fixed designation F 495; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test meth
3、od covers the determination of gasketmaterial weight loss upon exposure to elevated temperatures.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This test method may include hazardous materials,operations, and equipment
4、.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Significanc
5、e and Use2.1 Weight loss represents the amount of combustibles andvolatiles of the material at various temperatures between315C (600F) and 815C (1499F). This procedure should notbe used to determine percent of binder content.3. Apparatus3.1 Muffle Furnace, capable of maintaining a temperaturerange b
6、etween 315C (600F) and 815C (1499F) with anaccuracy of 65C (9F).3.2 Porcelain Crucible.3.3 Analytical Balance.3.4 Desiccator, containing anhydrous calcium chloride orsilica gel.3.5 Circulating Air Oven, maintained at 100 6 2C (21263.6F).4. Test Specimens4.1 Specimens shall consist ofa5to10-g quantit
7、y of thematerial. The specimens shall be cut into pieces not larger than12.7 mm (12 in.) square to allow all of it to be placed within thecrucible.5. Conditioning5.1 After the specimen has been cut or broken up and placedin the crucible, heat it in the circulating air oven for1hat100C (212F) and all
8、ow it to cool to 21 to 30C (70 to 86F)in the desiccator.6. Number of Tests6.1 A minimum of three tests shall be run on separatespecimens taken from the same sample with the resultsaveraged, unless otherwise agreed upon between the producerand the user.7. Procedure7.1 Heat a clean crucible for 30 min
9、 at the specified testtemperature. Cool to 21 to 30C (70 to 86F) in a desiccator.Weigh the crucible on the analytical balance and record as W1.7.2 Place the cut or broken-up specimen in the crucible andcondition in accordance with 5.1. Weigh the specimen andcrucible and record the weight as W2.7.3 P
10、lace the specimen and the crucible in the mufflefurnace at the temperature level determined for this test for 60min (recommend 61 min), cool the specimen and the crucibleto 21 to 30C (70 to 86F) in a desiccator, weigh the specimenand crucible and record the weight as W3.7.3.1 For tests at 815C (1499
11、F) the specimen should beignited initially in the crucible by supporting over a flame in anexhausted hood until the sample has extinguished.NOTE 1It is felt that the life of the heater elements in a muffle furnacewill be greatly extended if the majority of the organics in a specimen areburned off pr
12、ior to placing the crucible in the furnace.8. Calculations8.1 Calculate percent of weight loss as follows:Weight loss, % 5W22 W3!W22 W1!3 1009. Report9.1 Report the following information:9.1.1 Percent of weight loss, and1This test method is under the jurisdiction of ASTM Committee F03 on Gasketsand
13、is the direct responsibility of Subcommittee F03.40 on Chemical Test Methods.Current edition approved April 1, 2004. Published April 2004. Originallyapproved in 1977. Last previous edition approved in 1999 as F 495 99a.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
14、ken, PA 19428-2959, United States.9.1.2 Complete identification of the gasket material tested,including type, source, date of manufacture, thickness, manu-facturers designation, test temperature, etc.10. Precision and Bias10.1 The following data should be used for judging theacceptability of results
15、:10.1.1 Reproducibility (Multilaboratory)The coefficientof variation of results (each the average of duplicate determi-nations) obtained by analysis in different laboratories has beenestimated to be 12.4 % relative. Two such values should beconsidered suspect (95 % confidence) if they differ by more
16、than 25 % relative.11. Keywords11.1 combustibles; elevated temperatures; muffle furnace;volatiles; weight lossASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised
17、 that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either rea
18、pproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If yo
19、u feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 495 99a (2004)2
